Optical imaging lens and electronic device comprising the same

ABSTRACT

An optical imaging lens set includes a first lens element to a plastic fifth lens element from an object side toward an image side along an optical axis. The second lens element has an image-side surface with a convex portion in a vicinity of its periphery. The fourth lens element has an image-side surface with a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of its periphery.

CROSS-REFERENCE RELATED TO APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/093,533, filed on Dec. 2, 2013, which claims priority to ChinesePatent Application No. 201310288528.9, filed on Jul. 10, 2013, thedisclosure of which are hereby incorporated by reference in theirentirety for all purposes.

BACKGROUND OF THE INVENTION

The present invention generally relates to an optical imaging lens setand an electronic device which includes such optical imaging lens set.Specifically speaking, the present invention is directed to an opticalimaging lens set of five lens elements and an electronic device whichincludes such optical imaging lens set of five lens elements.

DESCRIPTION OF THE PRIOR ART

In recent years, the popularity of mobile phones and digital camerasmakes the photography modules of various portable electronic products,such as optical imaging lens elements or an image sensor developquickly, and the shrinkage of mobile phones and digital cameras alsomakes a greater and greater demand for the miniaturization of thephotography module. The current trend of research is to develop anoptical imaging lens set of a shorter length with uncompromised goodquality.

With the development and shrinkage of a charge coupled device (CCD) or acomplementary metal oxide semiconductor element (CMOS), the opticalimaging lens set installed in the photography module shrinks to meet thedemands as well. However, good and necessary optical properties, such asthe system aberration improvement, as well as production cost andproduction feasibility should be taken into consideration, too.

For example, JP 4197994, JP 2008-281760, TW M-369459, TW 200722785, US2010-0254029 and U.S. Pat. No. 8,248,713 all disclose an optical imaginglens set made of five lens elements. However, the total length of theoptical imaging lens set is longer than 9 mm so they are disadvantageousfor a smaller design.

These disclosed dimensions do not show good examples of the shrinkage ofportable electronic products, such as mobile phones and digital cameras.It is still a problem, on one hand, to reduce the system lengthefficiently and, on the other hand, to maintain a sufficient opticalperformance in this field.

SUMMARY OF THE INVENTION

In the light of the above, the present invention is capable of proposingan optical imaging lens set of lightweight, low production cost, reducedlength, high resolution and high image quality. The optical imaging lensset of five lens elements of the present invention has a first lenselement, a second lens element, a third lens element, a fourth lenselement and a fifth lens element sequentially from an object side to animage side along an optical axis.

The second lens element has an image-side surface facing toward theimage side and the image-side surface has a convex portion in a vicinityof a circular periphery of the second lens element. The fourth lenselement has an image-side surface facing toward the image side and theimage-side surface has a concave portion in a vicinity of the opticalaxis and a convex portion in a vicinity of a circular periphery of thefourth lens element. The fifth lens element is made of plastic. Theoptical imaging lens set exclusively has five lens elements withrefractive power. Each one of the first lens element, the second lenselement, the third lens element, the fourth lens element, and the fifthlens element has an object-side surface facing toward said object sideand an image-side surface facing toward said image side.

In the optical imaging lens set of five lens elements of the presentinvention, the first lens element has a first lens element thickness T₁along the optical axis, the second lens element has a second lenselement thickness T₂ along the optical axis, the third lens element hasa third lens element thickness T₃ along the optical axis, the fourthlens element has a fourth lens element thickness T₄ along the opticalaxis, and the fifth lens element has a fifth lens element thickness T₅along the optical axis, the total thickness of all the lens elements inthe optical imaging lens set along the optical axis isT_(a1)=T₁+T₂+T₃+T₄+T₅.

In the optical imaging lens set of five lens elements of the presentinvention, an air gap G₁₂ is disposed between the first lens element andthe second lens element, an air gap G₂₃ is disposed between the secondlens element and the third lens element, an air gap G₃₄ is disposedbetween the third lens element and the fourth lens element, an air gapG₄₅ is disposed between the fourth lens element and the fifth lenselement, the sum of total four air gaps between adjacent lens elementsfrom the first lens element to the fifth lens element along the opticalaxis is G_(aa)=G₁₂+G₂₃+G₃₄+G₄₅.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₄ of the fourth lens element along the opticalaxis and an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfy a relationship T₄/G₁₂≦2.0.

In the optical imaging lens set of five lens elements of the presentinvention, a focal length E_(fl) of the optical imaging lens set and ana thickness T₂ of the second lens element along the optical axis satisfya relationship 3.0≦(E_(fl)/T₂)≦7.0.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₁ of the first lens element along the opticalaxis and an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfy a relationship T₁/G₁₂≦2.5.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₂ of the second lens element along the opticalaxis and a thickness T₄ of the fourth lens element along the opticalaxis satisfy a relationship 1.4≦(T₂/T₄)≦3.5.

In the optical imaging lens set of five lens elements of the presentinvention, a focal length E_(fl) of the optical imaging lens set and athickness T₂ of the second lens element along the optical axis satisfy arelationship (E_(fl)/T₂)≦7.0.

In the optical imaging lens set of five lens elements of the presentinvention, a maximal thickness T_(max) among the five lens elementsalong the optical axis and an air gap G₁₂ between the first lens elementand the second lens element along the optical axis satisfy arelationship 0.7≦(T_(max)/G₁₂)≦2.3.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₁ of the first lens element along the opticalaxis and an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfy a relationship0.5≦T₁/G₁₂≦2.5.

In the optical imaging lens set of five lens elements of the presentinvention, a maximal thickness T_(max) among the five lens elementsalong the optical axis and a thickness T₂ of the second lens elementalong the optical axis satisfy a relationship T_(max)/T₂≦1.4.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₁ of the first lens element along the opticalaxis and the sum of all four air gaps G_(aa) between each lens elementfrom the first lens element to the fifth lens element along the opticalaxis satisfy a relationship 1.5≦G_(aa)/T_(1≦)4.0.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₂ of the second lens element along the opticalaxis satisfies a relationship T₁/T₂≦1.1.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₄ of the fourth lens element along the opticalaxis and the sum of all four air gaps G_(aa) between each lens elementfrom the first lens element to the fifth lens element along the opticalaxis satisfies a relationship 2.0≦G_(aa)/T₄≦8.0.

In the optical imaging lens set of five lens elements of the presentinvention, a thickness T₂ of the second lens element along the opticalaxis satisfies a relationship 1.4≦T₂/T₄.

In the optical imaging lens set of five lens elements of the presentinvention, an Abbe number VD₁ of the first lens element and an Abbenumber VD₂ of the second lens element satisfy a relationship 30≦VD₂−VD₁.

The present invention also proposes an electronic device which includesthe optical imaging lens set as described above. The electronic deviceincludes a case and an image module disposed in the case. The imagemodule includes an optical imaging lens set as described above, a barrelfor the installation of the optical imaging lens set, a module housingunit for the installation of the barrel, and an image sensor disposed atan image side of the optical imaging lens set.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first example of the optical imaging lens set ofthe present invention.

FIG. 2A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 2B illustrates the astigmatic aberration on the sagittal directionof the first example.

FIG. 2C illustrates the astigmatic aberration on the tangentialdirection of the first example.

FIG. 2D illustrates the distortion aberration of the first example.

FIG. 3 illustrates a second example of the optical imaging lens set offive lens elements of the present invention.

FIG. 4A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 4B illustrates the astigmatic aberration on the sagittal directionof the second example.

FIG. 4C illustrates the astigmatic aberration on the tangentialdirection of the second example.

FIG. 4D illustrates the distortion aberration of the second example.

FIG. 5 illustrates a third example of the optical imaging lens set offive lens elements of the present invention.

FIG. 6A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 6B illustrates the astigmatic aberration on the sagittal directionof the third example.

FIG. 6C illustrates the astigmatic aberration on the tangentialdirection of the third example.

FIG. 6D illustrates the distortion aberration of the third example.

FIG. 7 illustrates a fourth example of the optical imaging lens set offive lens elements of the present invention.

FIG. 8A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 8B illustrates the astigmatic aberration on the sagittal directionof the fourth example.

FIG. 8C illustrates the astigmatic aberration on the tangentialdirection of the fourth example.

FIG. 8D illustrates the distortion aberration of the fourth example.

FIG. 9 illustrates a fifth example of the optical imaging lens set offive lens elements of the present invention.

FIG. 10A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 10B illustrates the astigmatic aberration on the sagittal directionof the fifth example.

FIG. 10C illustrates the astigmatic aberration on the tangentialdirection of the fifth example.

FIG. 10D illustrates the distortion aberration of the fifth example.

FIG. 11 illustrates a sixth example of the optical imaging lens set offive lens elements of the present invention.

FIG. 12A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 12B illustrates the astigmatic aberration on the sagittal directionof the sixth example.

FIG. 12C illustrates the astigmatic aberration on the tangentialdirection of the sixth example.

FIG. 12D illustrates the distortion aberration of the sixth example.

FIG. 13 illustrates a seventh example of the optical imaging lens set offive lens elements of the present invention.

FIG. 14A illustrates the longitudinal spherical aberration on the imageplane of the seventh example.

FIG. 14B illustrates the astigmatic aberration on the sagittal directionof the seventh example.

FIG. 14C illustrates the astigmatic aberration on the tangentialdirection of the seventh example.

FIG. 14D illustrates the distortion aberration of the seventh example.

FIG. 15 illustrates exemplificative shapes of the optical imaging lenselement of the present invention.

FIG. 16 illustrates a first preferred example of the portable electronicdevice with an optical imaging lens set of the present invention.

FIG. 17 illustrates a second preferred example of the portableelectronic device with an optical imaging lens set of the presentinvention.

FIG. 18 shows the optical data of the first example of the opticalimaging lens set.

FIG. 19 shows the aspheric surface data of the first example.

FIG. 20 shows the optical data of the second example of the opticalimaging lens set.

FIG. 21 shows the aspheric surface data of the second example.

FIG. 22 shows the optical data of the third example of the opticalimaging lens set.

FIG. 23 shows the aspheric surface data of the third example.

FIG. 24 shows the optical data of the fourth example of the opticalimaging lens set.

FIG. 25 shows the aspheric surface data of the fourth example.

FIG. 26 shows the optical data of the fifth example of the opticalimaging lens set.

FIG. 27 shows the aspheric surface data of the fifth example.

FIG. 28 shows the optical data of the sixth example of the opticalimaging lens set.

FIG. 29 shows the aspheric surface data of the sixth example.

FIG. 30 shows the optical data of the seventh example of the opticalimaging lens set.

FIG. 31 shows the aspheric surface data of the seventh example.

FIG. 32 shows some important ratios in the examples.

DETAILED DESCRIPTION

Before the detailed description of the present invention, the firstthing to be noticed is that in the present invention, similar (notnecessarily identical) elements share the same numeral references. Inthe entire present specification, “a certain lens element hasnegative/positive refractive power” refers to the part in a vicinity ofthe optical axis of the lens element has negative/positive refractivepower. “An object-side/image-side surface of a certain lens element hasa concave/convex part or concave/convex portion” refers to the part ismore concave/convex in a direction parallel with the optical axis to becompared with an outer region next to the region. Take FIG. 15 forexample, the optical axis is “I” and the lens element is symmetricalwith respect to the optical axis I. The object side of the lens elementhas a convex part in the region A, a concave part in the region B, and aconvex part in the region C because region A is more convex in adirection parallel with the optical axis than an outer region (region B)next to region A, region B is more concave than region C and region C issimilarly more convex than region E. “A circular periphery of a certainlens element” refers to a circular periphery region of a surface on thelens element for light to pass through, that is, region C in thedrawing. In the drawing, imaging light includes Lc (chief ray) and Lm(marginal ray). “A vicinity of the optical axis” refers to an opticalaxis region of a surface on the lens element for light to pass through,that is, the region A in FIG. 15. In addition, the lens element mayinclude an extension part E for the lens element to be installed in anoptical imaging lens set. Ideally speaking, no light would pass throughthe extension part, and the actual structure and shape of the extensionpart is not limited to this and may have other variations. For thereason of simplicity, the extension part is not illustrated in FIGS. 1,3, 5, 7, 9, 11 and 13.

As shown in FIG. 1, the optical imaging lens set 1 of five lens elementsof the present invention, sequentially from an object side 2 (where anobject is located) to an image side 3 along an optical axis 4, has afirst lens element 10, a second lens element 20, a third lens element30, a fourth lens element 40, a fifth lens element 50, a filter 60 andan image plane 71. Generally speaking, the first lens element 10, thesecond lens element 20, the third lens element 30, the fourth lenselement 40 and the fifth lens element 50 may be made of a transparentplastic material and each has an appropriate refractive power, but thepresent invention is not limited to this and the fifth lens element 50is always made of a transparent plastic material. There are exclusivelyfive lens elements with refractive power in the optical imaging lens set1 of the present invention. The optical axis 4 is the optical axis ofthe entire optical imaging lens set 1, and the optical axis of each ofthe lens elements coincides with the optical axis of the optical imaginglens set 1.

Furthermore, the optical imaging lens set 1 includes an aperture stop(ape. stop) 80 disposed in an appropriate position. In FIG. 1, theaperture stop 80 is disposed between the first lens element 10 and thesecond lens element 20. When light emitted or reflected by an object(not shown) which is located at the object side 2 enters the opticalimaging lens set 1 of the present invention, it forms a clear and sharpimage on the image plane 71 at the image side 3 after passing throughthe first lens element 10, the aperture stop 80, the second lens element20, the third lens element 30, the fourth lens element 40, the fifthlens element 50 and the filter 60.

In the embodiments of the present invention, the optional filter 60 maybe a filter of various suitable functions, for example, the filter 60may be an infrared cut filter (IR cut filter) , placed between the fifthlens element 50 and the image plane 71.

Each lens element in the optical imaging lens set 1 of the presentinvention has an object-side surface facing toward the object side 2 aswell as an image-side surface facing toward the image side 3. Inaddition, each object-side surface and image-side surface in the opticalimaging lens set 1 of the present invention has a part in a vicinity ofits circular periphery (circular periphery part) away from the opticalaxis 4 as well as a part in a vicinity of the optical axis (optical axispart) closer to the optical axis 4. For example, the first lens element10 has an object-side surface 11 and an image-side surface 12; thesecond lens element 20 has an object-side surface 21 and an image-sidesurface 22; the third lens element 30 has an object-side surface 31 andan image-side surface 32; the fourth lens element 40 has an object-sidesurface 41 and an image-side surface 42; the fifth lens element 50 hasan object-side surface 51 and an image-side surface 52.

Each lens element in the optical imaging lens set 1 of the presentinvention further has a central thickness T on the optical axis 4. Forexample, the first lens element 10 has a first lens element thicknessT₁, the second lens element 20 has a second lens element thickness T₂,the third lens element 30 has a third lens element thickness T₃, thefourth lens element 40 has a fourth lens element thickness T₄, and thefifth lens element 50 has a fifth lens element thickness T₅. Therefore,the total thickness of all the lens elements in the optical imaging lensset 1 along the optical axis 4 is T_(a1)=T₁+T₂+T₃+T₄+T₅. At least one ofthe five lens elements has a maximal thickness T_(max) among all alongthe optical axis.

In addition, between two adjacent lens elements in the optical imaginglens set 1 of the present invention there is an air gap G along theoptical axis 4. For example, an air gap G₁₂ is disposed between thefirst lens element 10 and the second lens element 20, an air gap G₂₃ isdisposed between the second lens element 20 and the third lens element30, an air gap G₃₄ is disposed between the third lens element 30 and thefourth lens element 40, an air gap G₄₅ is disposed between the fourthlens element 40 and the fifth lens element 50. Therefore, the sum oftotal four air gaps between adjacent lens elements from the first lenselement 10 to the fifth lens element 50 along the optical axis 4 isG_(aa)=G₁₂+G₂₃+G₃₄+G₄₅.

FIRST EXAMPLE

Please refer to FIG. 1 which illustrates the first example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 2A for the longitudinal spherical aberration on the image plane 71of the first example; please refer to FIG. 2B for the astigmatic fieldaberration on the sagittal direction; please refer to FIG. 2C for theastigmatic field aberration on the tangential direction, and pleaserefer to FIG. 2D for the distortion aberration. The Y axis of thespherical aberration in each example is “field of view” for 1.0. The Yaxis of the astigmatic field and the distortion in each example standsfor “image height”.

The optical imaging lens set 1 of the first example has five lenselements 10 to 50; each is made of a plastic material and has refractivepower. The optical imaging lens set 1 also has a filter 60, an aperturestop 80, and an image plane 71. The aperture stop 80 is provided betweenthe first lens element 10 and the second lens element 20. The filter 60maybe an infrared filter (IR cut filter) to prevent inevitable infraredin light reaching the image plane to adversely affect the imagingquality.

The first lens element 10 has positive refractive power. The object-sidesurface 11 of the first lens element 10 facing toward the object side 2is a convex surface and the image-side surface 12 of the first lenselement 10 facing toward the image side 3 is a concave surface. Both theobject-side surface 11 and the image-side 12 of the first lens element10 are aspherical surfaces.

The second lens element 20 has positive refractive power. Theobject-side surface 21 of the second lens element 20 facing toward theobject side 2 is a convex surface and the image-side surface 22 of thesecond lens element 20 facing toward the image side 3 is a convexsurface and has a convex part 27 (convex circular periphery part) in avicinity of its circular periphery. In addition, both the object-sidesurface 21 and the image-side surface 22 of the second lens element 20are aspherical surfaces.

The third lens element 30 has positive refractive power, an object-sidesurface 31 of the third lens element 30 facing toward the object side 2and an image-side surface 32 of the third lens element 30 facing towardthe image side 3. The object-side surface 31 is a concave surface. Theimage-side surface 32 has a convex part 36 (convex optical axis part) inthe vicinity of the optical axis and a concave part 37 (concave circularperiphery part) in a vicinity of its circular periphery. In addition,both the object-side surface 31 and the mage-side surface 32 of thethird lens element 30 are aspherical surfaces.

The fourth lens element 40 has negative refractive power. Theobject-side surface 41 of the fourth lens element 40 facing toward theobject side 2 has a convex part 43 (convex optical axis part) in thevicinity of the optical axis and a concave part 44 (concave circularperiphery part) in a vicinity of its circular periphery. The image-sidesurface 42 of the fourth lens element 40 facing toward the image side 3has a concave part 46 (concave optical axis part) in the vicinity of theoptical axis and a convex part 47 (convex circular periphery part) in avicinity of its circular periphery. In addition, both the object-sidesurface 41 and the image-side 42 of the fourth lens element 40 areaspherical surfaces.

The fifth lens element 50 has positive refractive power, an object-sidesurface 51 of the fifth lens element 50 facing toward the object side 2and an image-side surface 52 of the fifth lens element 50 facing towardthe image side 3. The object-side surface 51 has a convex part 53(convex optical axis part) in the vicinity of the optical axis and aconcave part 54 (concave circular periphery part) in a vicinity of itscircular periphery. The image-side surface 52 has a concave part 56(concave optical axis part) in the vicinity of the optical axis and aconvex part 57 (convex circular periphery part) in a vicinity of itscircular periphery. Further, both the object-side surface 51 and theimage-side 52 of the fifth lens element 50 are aspherical surfaces. Thefilter 60 may be an infrared cut filter, and is disposed between thefifth lens element 50 and the image plane 71.

In the optical imaging lens element 1 of the present invention, theobject side 11/21/31/41/51 and image side 12/22/32/42/52 from the firstlens element 10 to the fifth lens element 50, total of ten surfaces areall aspherical. These aspheric coefficients are defined according to thefollowing formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}{a_{2i} \times Y^{2i}}}}$

in which:

R represents the curvature radius of the lens element surface;

Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);

Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;

K is a conic constant;

a_(2i), is the aspheric coefficient of the 2i order.

The optical data of the first example of the optical imaging lens set 1are shown in FIG. 18 and the Abbe No. is the Abbe number while theaspheric surface data are shown in FIG. 19. In the following examples ofthe optical imaging lens set, the f-number of the entire optical lenselement system is Fno, HFOV stands for the half field of view which ishalf of the field of view of the entire optical lens element system, andthe unit for the curvature radius, the thickness and the focal length isin millimeters (mm), and F is a system focal length Efl of the opticalimaging lens set 1. The length of the optical imaging lens set is 3.78mm (from the first object-side surface to the image plane along theoptical axis). The image height is 2.268 mm. Some important ratios ofthe first example are as follows:

-   T₄/G₁₂=1.906-   E_(fl)/T₂=3.382-   T₂/T₄=2.361-   T₁/G₁₂=2.490-   T_(max)/G₁₂=4.501-   T_(max)/T₂=1.000-   G_(aa)/T₁=1.654-   T₁/T₂=0.553-   G_(aa)/T₄=2.161-   V_(D2)−V_(D1)=32.586

SECOND EXAMPLE

Please refer to FIG. 3 which illustrates the second example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 4A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 4B for the astigmaticaberration on the sagittal direction; please refer to FIG. 4C for theastigmatic aberration on the tangential direction, and please refer toFIG. 4D for the distortion aberration. The second example is similarwith the first example, but the optical data, the object-side surface21, the image-side surface 32 are different. The object-side surface 21of the second lens element 20 is a concave surface and the image-sidesurface 32 of the third lens element 30 is a convex surface. The opticaldata of the second example of the optical imaging lens set are shown inFIG. 20 while the aspheric surface data are shown in FIG. 21. The lengthof the optical imaging lens set is 4.17 mm. The image height is 2.268mm. Some important ratios of the second example are as follows:

-   T₄/G₁₂=0.360-   E_(fl)/T₂=5.998-   T₂/T₄=1.852-   T₁/G₁₂=0.587-   T_(max)/G₁₂=0.933-   T_(max)/T₂=1.398-   G_(aa)/T_(i)=3.682-   T₁/T₂=0.880-   G_(aa)/T₄=6.000-   V_(D2)−V_(D1)=32.586

THIRD EXAMPLE

Please refer to FIG. 5 which illustrates the third example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 6A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 6B for the astigmaticaberration on the sagittal direction; please refer to FIG. 6C for theastigmatic aberration on the tangential direction, and please refer toFIG. 6D for the distortion aberration. The third example is similar withthe first example, but the optical data, the object-side surface 21, andthe image-side surface 32 are different. The object-side surface 21 ofthe second lens element 20 has a convex part 23 (convex optical axispart) in the vicinity of the optical axis and a concave part 24 (concavecircular periphery part) in a vicinity of its circular periphery and theimage-side surface 32 of the third lens element 30 is a convex surface.The optical data of the third example of the optical imaging lens setare shown in FIG. 22 while the aspheric surface data are shown in FIG.23. The length of the optical imaging lens set is 4.04 mm. The imageheight is 2.268 mm. Some important ratios of the third example are asfollows:

-   T₄/G₁₂=0.501-   E_(fl)/T₂=4.417-   T₂/T₄=1.811-   T₁/G₁₂=0.699-   T_(max)/G12=0.973-   T_(max)/T₂=1.072-   G_(aa)/T₁=2.844-   T₁/T₂=0.770-   G_(aa)/T₄=3.966-   V_(D2)−V_(D1)=32.586

FOURTH EXAMPLE

Please refer to FIG. 7 which illustrates the fourth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 8A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 8B for the astigmaticaberration on the sagittal direction; please refer to FIG. 8C for theastigmatic aberration on the tangential direction, and please refer toFIG. 8D for the distortion aberration. The fourth example is similarwith the first example, but the optical data, the object-side surface21, the image-side surface 32 are different. The object-side surface 21of the second lens element 20 has a convex part 23 (convex optical axispart) in the vicinity of the optical axis and a concave part 24 (concavecircular periphery part) in a vicinity of its circular periphery and theimage-side surface 32 of the third lens element is a convex surface. Theoptical data of the fourth example of the optical imaging lens set areshown in FIG. 24 while the aspheric surface data are shown in FIG. 25.The length of the optical imaging lens set is 4.04 mm. The image heightis 2.268 mm. Some important ratios of the fourth example are as follows:

-   T₄/G₁₂=0.767-   E_(fl)/T₂=2.574-   T₂/T₄=3.078-   T₁/G₁₂=1.177-   T_(max)/G₁₂=2.360-   T_(max)/T₂=1.000-   G_(aa)/T₁=1.783-   T₁/T₂=0.499-   G_(aa)/T₄=2.737-   V_(D2)−V_(D1)=32.586

FIFTH EXAMPLE

Please refer to FIG. 9 which illustrates the fifth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 10A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 10B for the astigmaticaberration on the sagittal direction; please refer to FIG. 100 for theastigmatic aberration on the tangential direction, and please refer toFIG. 10D for the distortion aberration. The fifth example is similarwith the first example, but the optical data and the image-side surface32 are different. The image-side surface 32 of the third lens element 30is a convex surface. The optical data of the fifth example of theoptical imaging lens set are shown in FIG. 26 while the aspheric surfacedata are shown in FIG. 27. The length of the optical imaging lens set is4.04 mm. The image height is 2.268 mm. Some important ratios of thefifth example are as follows:

-   T₄/G₁₂=0.981-   E_(fl)/T₂=3.342-   T₂/T₄=1.823-   T₁/G₁₂=1.308-   T_(max)/G₁₂=1.788-   T_(max)/T₂=1.000-   G_(aa)/T₁=1.501-   T₁/T₂=0.732-   G_(aa)/T₄=2.003-   V_(D2)−V_(DD)=32.586

SIXTH EXAMPLE

Please refer to FIG. 11 which illustrates the sixth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 12A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 12B for the astigmaticaberration on the sagittal direction; please refer to FIG. 12C for theastigmatic aberration on the tangential direction, and please refer toFIG. 12D for the distortion aberration. The sixth example is similarwith the first example, but the optical data and the image-side surface32 are different. The image-side surface 32 of the third lens element 30is a convex surface. The optical data of the sixth example of theoptical imaging lens set are shown in FIG. 28 while the aspheric surfacedata are shown in FIG. 29. The length of the optical imaging lens set is3.74 mm. The image height is 2.268 mm. Some important ratios of thesixth example are as follows:

-   T₄/G₁₂=0.971-   E_(fl)/T₂=5.477-   T₂/T₄=1.489-   T₁/G₁₂=0.944-   T_(max)/G₁₂=2.016-   T_(max)/T₂=1.394-   G_(aa)/T₁=3.358-   T₁/T₂=0.653-   G_(aa)/T₄=3.264-   V_(D2)−V_(D1)=32.586

SEVENTH EXAMPLE

Please refer to FIG. 13 which illustrates the seventh example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 14A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 14B for the astigmaticaberration on the sagittal direction; please refer to FIG. 14C for theastigmatic aberration on the tangential direction, and please refer toFIG. 14D for the distortion aberration. The seventh example is similarwith the first example, but the optical data, refractive power of thefirst lens element 10, the object-side surface 21 and the image-sidesurface 32 are different. The first lens element 10 has negativerefractive power, the object-side surface 21 of the second lens element20 has a convex part 23 (convex optical axis part) in the vicinity ofthe optical axis and a concave part 24 (concave circular periphery part)in a vicinity of its circular periphery and the image-side surface 32 ofthe third lens element 30 is a convex surface. The optical data of theseventh example of the optical imaging lens set are shown in FIG. 30while the aspheric surface data are shown in FIG. 31. The length of theoptical imaging lens set is 3.89 mm. The image height is 2.268 mm. Someimportant ratios of the sixth example are as follows:

-   T₄/G₁₂=0.673-   E_(fl)/T₂=5.435-   T₂/T₄=1.741-   T₁/G₁₂=0.904-   T_(max)/G₁₂=1.463-   T_(max)/T₂=1.250-   G_(aa)/T₁=3.368-   T₁/T₂=0.772-   G_(aa)/T₄=4.527-   V_(D2)−V_(D1)=32.586

Some important ratios in each example are shown in FIG. 32.

In the light of the above examples, the inventors observe the followingfeatures:

-   1) The convex circular periphery part of the image-side surface of    the second lens element and the concave optical axis part as well as    the convex circular periphery part of the fourth image-side surface    of the fourth lens element work together to minimize the    aberrations.-   2) The plastic fifth lens element facilitates the reduction of the    production cost and the reduction of the weight of the optical    imaging lens set.

In addition, it is found that there are some better ratio ranges fordifferent optical data according to the above various important ratios.Better ratio ranges help the designers to design the better opticalperformance and an effectively reduced length of a practically possibleoptical imaging lens set. For example:

-   1. T₄/G₁₂ should be not greater than 2.0. When the optical imaging    lens set is smaller, the total length should be shorter as well.    However, because the concave optical axis part of the image-side    surface of the fourth lens element, it may be thinner to satisfy    this relationship. It is suggested that 0.1≦T₄/G₁₂≦2.0.-   2. E_(fl)/T₂ should be not greater than 7.0. When the optical    imaging lens set is shorter, the focal length should be shorter as    well to satisfy this relationship. Preferably, it is    3.0≦E_(fl)/T_(2≦)7.0. A smaller T₂ helps to optimize a better    arrange of other lens thickness and gaps when the optical imaging    lens set becomes shorter. Or, it is 2.0≦E_(fl)/T₂≦7.0.-   3. T₂/T₄ should be not less than 1.4. When the optical imaging lens    set is smaller, the total length should be shorter as well. However,    because the concave optical axis part of the image-side surface of    the fourth lens element, it may be thinner to satisfy this    relationship. It is suggested that 1.4≦T₂/T₄≦3.5.-   4. T₁/G₁₂ should be not greater than 2.5. When the optical imaging    lens set is smaller, the total length should be shorter as well.    When the optical performance and the productivity are taken into    consideration, this relationship suggests better results.    Preferably, it is 0.5≦T₁/G₁₂≦2.5.-   5. T_(max)/G₁₂ should be between 0.7 and 2.3. When the optical    imaging lens set is smaller, the total length should be shorter and    the largest thickness should become smaller as well to satisfy this    relationship. 6. T_(max)/T₂ should be not greater than 1.4. When the    optical imaging lens set is smaller, the total length should be    shorter and the largest thickness should become smaller as well to    satisfy this relationship. Preferably, It is suggested that    0.8≦T_(max)/T₂≦1.4.-   7. G_(aa)/T₁ should be between 1.5 and 4.0. When the optical imaging    lens set is smaller, the total length should be shorter as well.    When the optical performance and the productivity are taken into    consideration, this relationship suggests better results.-   8. T₁/T₂ should be not greater than 1.1. When the optical imaging    lens set is smaller, the total length should be shorter as well.    When the optical performance and the productivity are taken into    consideration, this relationship suggests better results.    Preferably, it is suggested that 0.3≦T₁/T₂≦1.1.-   9. G_(aa)/T₄ should be between 2.0 and 8.0. When the optical imaging    lens set is smaller, the total length should be shorter as well.    When the optical performance and the productivity are taken into    consideration, this relationship suggests better results.-   10. V_(D2)−V_(D1) should be not less than 30. Abbe Number is used to    evaluate the dispersion properties of a lens. A shortened lens set    would have worse dispersion properties. This relationship    facilitates to reduce the dispersion properties.    30≦V_(D2)−V_(D1)≦36.

The optical imaging lens set 1 of the present invention may be appliedto a portable electronic device. Please refer to FIG. 16. FIG. 16illustrates a first preferred example of the optical imaging lens set 1of the present invention for use in a portable electronic device 100.The portable electronic device 100 includes a case 110, and an imagemodule 120 mounted in the case 110. A mobile phone is illustrated inFIG. 16 as an example, but the portable electronic device 100 is notlimited to a mobile phone.

As shown in FIG. 16, the image module 120 includes the optical imaginglens set 1 as described above. FIG. 16 illustrates the aforementionedfirst example of the optical imaging lens set 1. In addition, theportable electronic device 100 also contains a barrel 130 for theinstallation of the optical imaging lens set 1, a module housing unit140 for the installation of the barrel 130, a substrate 172 for theinstallation of the module housing unit 140 and an image sensor 70disposed at the substrate 172, and at the image side 3 of the opticalimaging lens set 1.

The image sensor 70 in the optical imaging lens set 1 may be anelectronic photosensitive element, such as a charge coupled device or acomplementary metal oxide semiconductor element. The image plane 71forms at the image sensor 70.

The image sensor 70 used here is a product of chip on board (COB)package rather than a product of the conventional chip scale package(CSP) so it is directly attached to the substrate 172, and protectiveglass is not needed in front of the image sensor 70 in the opticalimaging lens set 1, but the present invention is not limited to this.

To be noticed in particular, the optional filter 60 may be omitted inother examples although the optional filter 60 is present in thisexample. The case 110, the barrel 130, and/or the module housing unit140 may be a single element or consist of a plurality of elements, butthe present invention is not limited to this.

Each one of the five lens elements 10, 20, 30, 40 and 50 with refractivepower is installed in the barrel 130 with air gaps disposed between twoadjacent lens elements in an exemplary way. The module housing unit 140has a lens element housing 141, and an image sensor housing 146installed between the lens element housing 141 and the image sensor 70.However in other examples, the image sensor housing 146 is optional. Thebarrel 130 is installed coaxially along with the lens element housing141 along the axis I-I′, and the barrel 130 is provided inside of thelens element housing 141.

Because the optical imaging lens set 1 of the present invention may beas short as 3.78 mm, this ideal length allows the dimensions and thesize of the portable electronic device 100 to be smaller and lighter,but excellent optical performance and image quality are still possible.In such a way, the various examples of the present invention satisfy theneed for economic benefits of using less raw materials in addition tosatisfy the trend for a smaller and lighter product design andconsumers' demands.

Please also refer to FIG. 17 for another application of theaforementioned optical imaging lens set 1 in a portable electronicdevice 200 in the second preferred example. The main differences betweenthe portable electronic device 200 in the second preferred example andthe portable electronic device 100 in the first preferred example are:the lens element housing 141 has a first seat element 142, a second seatelement 143, a coil 144 and a magnetic component 145. The first seatelement 142 is for the installation of the barrel 130, exteriorlyattached to the barrel 130 and disposed along the axis IT. The secondseat element 143 is disposed along the axis I-I′ and surrounds theexterior of the first seat element 142. The coil 144 is provided betweenthe outside of the first seat element 142 and the inside of the secondseat element 143. The magnetic component 145 is disposed between theoutside of the coil 144 and the inside of the second seat element 143.

The first seat element 142 may pull the barrel 130 and the opticalimaging lens set 1 which is disposed inside of the barrel 130 to movealong the axis IT, namely the optical axis 4 in FIG. 1. The image sensorhousing 146 is attached to the second seat element 143. The filter 60,such as an infrared filter, is installed at the image sensor housing146. Other details of the portable electronic device 200 in the secondpreferred example are similar to those of the portable electronic device100 in the first preferred example so they are not elaborated again.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens set comprising: a firstlens element having an image-side surface facing toward an image sideand an object-side surface facing toward an object side; a second lenselement having an image-side surface facing toward the image side and anobject-side surface facing toward the object side; a third lens elementhaving an image-side surface facing toward the image side and anobject-side surface facing toward the object side; a fourth lens elementhaving an image-side surface facing toward the image side and anobject-side surface facing toward the object side; and a fifth lenselement having an image-side surface facing toward the image side and anobject-side surface facing toward the object side, wherein the first,second, third, fourth, and fifth lens elements are disposed from theobject side toward the image side in order along an optical axis andeach lens element has a refractive power, wherein: the image-sidesurface of the first lens element has a concave portion in a vicinity ofthe optical axis; the image-side surface of the second lens element hasa convex portion in a vicinity of the optical axis; the image-sidesurface of the fourth lens element has a concave portion in a vicinityof the optical axis; and the image-side surface of the fifth lenselement has a concave portion in a vicinity of the optical axis; whereina total thickness of the first, second, third, fourth, and fifth lenselements along the optical axis is equal to T_(a1), a thickness of thesecond lens element along the optical axis is equal to T₂, and T_(a1)and T₂ satisfy a relationship T_(a1)/T₂≦4.82.
 2. The optical imaginglens set of claim 1 wherein an air gap between the first lens elementand the second lens element along the optical axis is equal to G₁₂,wherein T_(a1) and G₁₂ satisfy a relationship 3.19≦T_(a1)/G₁₂.
 3. Theoptical imaging lens set of claim 2 wherein a thickness of the fifthlens element along the optical axis is equal to T₅, and T_(a1) and T₅satisfy a relationship T_(a1)/T₅≦6.90.
 4. The optical imaging lens setof claim 1 wherein a thickness of the third lens element along theoptical axis is equal to T₃, and T_(a1) and T₃ satisfy a relationshipT_(a1)/T₃≦4.82.
 5. The optical imaging lens set of claim 4 wherein athickness of the fourth lens element along the optical axis is equal toT₄, and T_(a1) and T₄ satisfy a relationship T_(a1)/T₄≦8.85.
 6. Theoptical imaging lens set of claim 1 wherein an air gap between thesecond lens element and the third lens element along the optical axis isequal to G₂₃, wherein T_(a1) and G₂₃ satisfy a relationship3.52≦T_(a1)/G₂₃.
 7. The optical imaging lens set of claim 6 wherein asum of air gaps between adjacent lens elements from the first lenselement to the fifth lens element along the optical axis is G_(aa), andT_(a1) and G_(aa) satisfy a relationship T_(a1)+G_(aa)≦3.06.
 8. Theoptical imaging lens set of claim 1 wherein an abbe number VD₁ of thefirst lens element and an abbe number VD₂ of the second lens elementsatisfy a relationship 20≦|VD₁−VD₂|.
 9. The optical imaging lens set ofclaim 8 wherein a thickness of the first lens element along the opticalaxis is equal to T₁ and an air gap between the first lens element andthe second lens element along the optical axis is equal to G₁₂, whereinT₁ and G₁₂ satisfy a relationship 0.59≦T₁/G₁₂.
 10. The optical imaginglens set of claim 1 wherein a thickness of the second lens element alongthe optical axis is equal to T₂ and an air gap between the first lenselement and the second lens element along the optical axis is equal toG₁₂, wherein T₂ and G₁₂ satisfy a relationship 0.67≦T₂/G₁₂.
 11. Theoptical imaging lens set of claim 10 wherein an abbe number VD₂ of thesecond lens element and an abbe number VD₄ of the fourth lens elementsatisfy a relationship |VD₂−VD₄|≦10.
 12. The optical imaging lens set ofclaim 1 wherein a thickness of the first lens element along the opticalaxis is equal to T₁ and a thickness of the fifth lens element along theoptical axis is equal to T₅, wherein T₁ and T₅ satisfy a relationshipT₅/T₁≦1.61.
 13. The optical imaging lens set of claim 12 wherein athickness of the first lens element along the optical axis is equal toT₁, and T_(aa) and T₁ satisfy a relationship T_(a1)/T₁≦7.24.
 14. Theoptical imaging lens set of claim 1 further comprising an aperture stopdisposed between the first lens element and the second lens element. 15.The optical imaging lens set of claim 14 wherein an abbe number VD₁ ofthe first lens element and an abbe number VD₅ of the fifth lens elementsatisfy a relationship 20≦|VD₁−VD₅|.
 16. The optical imaging lens set ofclaim 1 wherein the second lens element has a positive refracting power.17. The optical imaging lens set of claim 16 wherein the third lenselement has a positive refracting power.
 18. The optical imaging lensset of claim 17 wherein the first lens element has a negative refractingpower.